If you need any extra functionality Python developers ansd usrs alike know well of speed issues with Python when you come down to raw data processing - like pixel processing: the idea with Python is simply leave the pixel manipualtion per se for binary code accessible through a wrapper.

Therefore, there is a stalemate there. The most a "pure python image module" search yields is a library to parse JPEG files. It would not be hard to assemble a small library that could deal with a limited numebr of formats for a few basic operations, though it would be slow.

(MAybe it is possible to use Corepy (http://www.corepy.org/) to dinamically create binary code inside GAE - but I doubt so. It wouldb e an interesting experiment though- although it is pure Python, chances are there are sandboxing barriers in place to prevent Corepy from working)

Another alternative is to set-up an image processing API yourself, using one of various Python binary modules for manipluating images likePython Sig, PIL, PyGegl, Pyleptonica, PythonMagick on another server, and use jsonrpc from GAE to process the images remotely.